The advent of the computer has already had a profound effect upon human society, and the impact of processing technology is expected to increase. Indeed, the desirability to store information for subsequent retrieval currently grows at an exponential rate. Thus, various types of devices have been developed to store data both for on-line usage as well as for archival purposes.
Where on-line processing requires data to be readily at hand, a significant improvement was provided by the advent of the magnetic disk storage array. Here, one or more magnetic disks are provided, and a read/write recording head is used to record information on the disk as well as to retrieve information or data for use by the computer processor. Significant strides have been made in the ability to increase the density of data stored on such magnetic disk arrays. In order to gain an even higher density for on-line data, the optical disk was developed. These devices record data based upon a very small wavelength of light so that a higher density is obtained due to this technique. Laser light is employed to read the stored information or data on the optical disk.
In early days of the computer, before the advent of the magnetic disks and the optical disk storage assemblies, data was typically stored on magnetic tapes, such as reel-to-reel tapes and later cassettes or cartridges. In a magnetic tape storage device, a magnetic coil is used as a transducer to imprint data magnetically on a moving band of magnetic film; thereafter, when the film is advanced across the transducer, the data may be read and re-input into a co-processor. Magnetic tape can be erased and rewritten many times and has an advantage of low cost.
Magnetic tape is still a highly desirable format for archiving data for rapid access is of less significance and cost is of concern. However, where vast quantities of data are to be maintained, these tapes can be bulky due to the physical number necessary to store the quantity of data. The capacity for such tapes to store data, of course, is dependent upon the number of “tracks” which can be independently placed across the width of the tape.
The ability to write data rapidly onto a magnetic tape film and the accessibility of data to be read from the film is a function of two variables: (1) the density of storage; and (2) the speed at which the tape medium may be transported across and accurately written/read by the transducer. Thus, for example, a magnetic tape read/write system that is able to read and write nine tracks of data on a single strip of tape will hold four and one-half times the amount of data as a system which only utilizes two tracks. Therefore, efforts to increase the capacity of magnetic tapes to store data have included substantial efforts to increase the number of tracks which can be written on a band of magnetic tape.
In the above-described systems, storage reels of tape, whether flanged or flange-less (for example as used in cartridges) may be placed on the machine during use. A threading assembly engages the free end of the tape and passes it through the machine. Typically, the tape is threaded across air bearings, past the transducer and into a take-up hub or reel. The length of the tape is then passed through the machine so that information may be placed on the tape or retrieved therefrom. During this process, the length of tape is transferred onto a take-up reel or hub that is either a part of the machine itself, included within the cartridge or that is mounted and demounted from such machine. After being transported through the machine, the tape may be rewound onto the storage reel and removed from the machine.
In the tape cartridge read/write recording system of the type identified above, it is necessary to insert a cartridge into the machine so that the tape medium contained within the cartridge may be threaded through the machine to perform a read/write function thereon. While this can accomplished manually, most systems incorporate automated assemblies, such as an automated tape library system, that will initially place a tape cartridge in the read/write recording system to define a received state for the cartridge. The read/write recording system is then actuated to retract the tape cartridge and mount it in the read/write recording assembly. After performance of the read/write recording function, the read/write recording assembly demounts the cartridge and extends it so that the tape cartridge may again be retrieved by the automated library system.
The present invention is directed to a tape cartridge docking apparatus associated with a read/write recording assembly that receives the tape cartridge, mounts the tape cartridge and demounts the tape cartridge from the read/write assembly. The invention is also directed to a read/write recording assembly incorporating such docking apparatus as well as the methods accomplished by the docking apparatus.